Trailer-based energy capture and management

ABSTRACT

A through the road (TTR) hybridization strategy is proposed to facilitate introduction of hybrid electric vehicle technology in a significant portion of current and expected trucking fleets. In some cases, the technologies can be retrofitted onto an existing vehicle (e.g., a trailer, a tractor-trailer configuration, etc.). In some cases, the technologies can be built into new vehicles. In some cases, one vehicle may be built or retrofitted to operate in tandem with another and provide the hybridization benefits contemplated herein. By supplementing motive forces delivered through a primary drivetrain and fuel-fed engine with supplemental torque delivered at one or more electrically-powered drive axles, improvements in overall fuel efficiency and performance may be delivered, typically without significant redesign of existing components and systems that have been proven in the trucking industry.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation-in-part of U.S. patent applicationSer. No. 15/618,737 filed on Jun. 9, 2017, which is a continuation ofU.S. patent application Ser. No. 15/144,769, which claims priority fromU.S. Provisional Patent Application No. 62/179,209. This applicationadditionally claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Patent Application Nos. 62/403,000, filed Sep. 30, 2016, and62/460,734, filed Feb. 17, 2017. U.S. Provisional Patent ApplicationNos. 62/403,000 and 62/460,734 are each incorporated by referenceherein.

BACKGROUND Field of the Invention

The invention relates generally to hybrid vehicle technology, and inparticular to systems and methods to intelligently control regenerationand reuse of captured energy in a through-the-road (TTR) hybridconfiguration.

Description of the Related Art

The U.S. trucking industry consumes about 51 billion gallons of fuel peryear, accounting for over 30% of overall industry operating costs. Inaddition, the trucking industry spends over $100 billion on fuelannually, and the average fuel economy of a tractor-trailer (e.g., an18-wheeler) is only about 6.5 miles per gallon. For trucking fleetsfaced with large fuel costs, techniques for reducing those costs wouldbe worth considering.

Hybrid technology has been in development for use in the truckingindustry for some time, and some hybrid trucks have entered the market.However, existing systems are generally focused on hybridizing thedrivetrain of a heavy truck or tractor unit, while any attached traileror dead axles remain a passive load. Thus, the extent to which the fuelefficiency of a trucking fleet may be improved using these technologiesmay be limited to the fuel efficiencies obtained from improvement of thehybrid drivetrain and the in-fleet adoption of such hybrid drivetraintechnologies. Given the large numbers of heavy trucks and tractor unitsalready in service and their useful service lifetimes (often 10-20years), the improved hybrid drivetrains that are candidates forintroduction in new vehicles would only address a small fraction ofexisting fleets. Improved techniques, increased adoption, and newfunctional capabilities are all desired.

SUMMARY

It has been discovered that a through-the-road (TTR) hybridizationstrategy can facilitate introduction of hybrid electric vehicletechnology in a significant portion of current and expected truckingfleets. In some cases, the technologies can be retrofitted onto anexisting vehicle (e.g., a truck, a tractor unit, a trailer, atractor-trailer configuration, at a tandem, etc.). In some cases, thetechnologies can be built into new vehicles. In some cases, one vehiclemay be built or retrofitted to operate in tandem with another andprovide the hybridization benefits contemplated herein. By supplementingmotive forces delivered through a primary drivetrain and fuel-fed enginewith supplemental torque delivered at one or more electrically-powereddrive axles, improvements in overall fuel efficiency and performance maybe delivered, typically without significant redesign of existingcomponents and systems that have been proven in the trucking industry.

In general, through-the-road (TTR) designs using control strategies suchas an equivalent consumption minimization strategy (ECMS) or adaptiveECMS are contemplated and implemented at the supplemental torquedelivering electrically-powered drive axle (or axles) in a manner thatfollows operational parameters or computationally estimates states ofthe primary drivetrain and/or fuel-fed engine, but does not itselfparticipate in control of the fuel-fed engine or primary drivetrain.Instead, techniques of the present invention rely on operatingparameters that can be observed and/or kinematic variables that aresensed to inform its controller.

In some embodiments, an ECMS-type controller for theelectrically-powered drive axle is not directly responsive to driver-,autopilot- or cruise-type throttle controls of the fuel-fed engine orgear selections by a driver or autopilot in the primary drivetrain.Instead, the controller is responsive to sensed pressure in a brake linefor regenerative braking, to computationally-estimated operationalstates of the fuel-fed engine or of the drive train, and to other sensedparameters. In some cases, observables employed by the controllerinclude information retrievable via a CANbus or SAE J1939 vehicle businterface such as commonly employed in heavy-duty trucks. While theECMS-type controller employed for the electrically-powered drive axle(or axles) adapts to the particular characteristics and currentoperation of the fuel-fed engine and primary drivetrain (e.g., apparentthrottle and gearing), it does not itself control the fuel-fed engine orof the primary drivetrain.

In some embodiments of the present invention, an apparatus includes: atowed vehicle for use in combination with a towing vehicle, the towedvehicle having an electrically powered drive axle configured to supplysupplemental torque to one or more wheels of the towed vehicle and tothereby supplement, while the towed vehicle travels over a roadway andin at least some modes of operation, primary motive forces appliedthrough a separate drivetrain of the towing vehicle; an energy store onthe towed vehicle, the energy store configured to supply theelectrically powered drive axle with electrical power and furtherconfigured to receive energy recovered using the drive axle in aregenerative braking mode of operation; and an electrical powerinterface to supply electrical power from the energy store to the towingvehicle.

In some embodiments, the apparatus further includes the towing vehicle;and a heating, ventilation or cooling system on the towing vehicle, theheating, ventilation or cooling system coupled to receive electricalpower from the energy store on the towed vehicle via the electricalpower interface.

In some embodiments, the energy store on the towed vehicle includes abattery or battery array.

In some embodiments, the apparatus further includes an inverter coupledbetween the battery or battery array and the electrical power interfaceto supply AC power to the towing vehicle.

In some embodiments, the apparatus further includes a step-down DC-DCpower supply coupled between the battery or battery array and theelectrical power interface to supply DC power to the towing vehicle.

In some embodiments, the apparatus further includes an electrical cablefor transferring electrical power from the energy store on the towedvehicle to towing vehicle and for bidirectionally conveying data betweenthe towing vehicle and at least a battery management system of the towedvehicle.

In some embodiments, the apparatus further includes a control interfacein the towing vehicle, the control interface coupled to the batterymanagement system of the towed vehicle via the electrical cable, thecontrol interface providing one of more of: in-towing-vehicle display ofstate of charge for the energy store on the towed vehicle; a switch orcontrol of a switch to enable and disable supply of electrical power tothe towing vehicle; and mode control for selectively controlling anoperating mode of the battery management system, wherein in at least oneselectable mode, energy recovered using the drive axle in a regenerativebraking mode is used to bring the energy store to a substantially fullstate of charge, and wherein in at least another selectable mode, stateof charge is managed to a dynamically varying level based at least inpart on uphill and downhill grades along current or predicted route oftravel.

In some embodiments, the control interface is integrated with a heating,ventilation or cooling system on the towing vehicle, the heating,ventilation or cooling system powered from the energy store on the towedvehicle at least during some extended periods of time during which anengine of the towing vehicle is off.

In some embodiments of the present invention, a method includes:supplying supplemental torque to one or more wheels of a towed vehicleusing an electrically powered drive axle on the towed vehicle tosupplement, while the towed vehicle travels over a roadway and in atleast some modes of operation, primary motive forces applied through aseparate drivetrain of a towing vehicle; supplying the electricallypowered drive axle with electrical power from an energy store on thetowed vehicle, the energy store configured to receive and store energyrecovered using the drive axle in a regenerative braking mode ofoperation; and supplying electrical power to the towing vehicle from theenergy store on the towed vehicle.

In some embodiments, the method further includes supplying electricalpower from the energy store on the towed vehicle to a heating,ventilation or cooling system on the towing vehicle.

In some embodiments, the energy store on the towed vehicle includes abattery or battery array.

In some embodiments, the method further includes using an invertercoupled between the battery or battery array and the electrical powerinterface to supply AC power to the towing vehicle.

In some embodiments, the method further includes using a step-down DC-DCpower supply coupled between the battery or battery array and theelectrical power interface to supply DC power to the towing vehicle.

In some embodiments, the method further includes transferring electricalpower from the energy store on the towed vehicle to towing vehicle viaan electrical cable; and bidirectionally conveying data between thetowing vehicle and at least a battery management system of the towedvehicle via the electrical cable.

In some embodiments, the method further includes providing a controlinterface in the towing vehicle, the control interface coupled to thebattery management system of the towed vehicle via the electrical cable,the control interface including one of more of: in-towing-vehicledisplay of state of charge for the energy store on the towed vehicle; aswitch or control of a switch to enable and disable supply of electricalpower to the towing vehicle; and mode control for selectivelycontrolling an operating mode of the battery management system, whereinin at least one selectable mode, energy recovered using the drive axlein a regenerative braking mode is used to bring the energy store to asubstantially full state of charge, and wherein in at least anotherselectable mode, state of charge is managed to a dynamically varyinglevel based at least in part on uphill and downhill grades along currentor predicted route of travel.

In some embodiments, the control interface is integrated with theheating, ventilation or cooling system on the towing vehicle, theheating, ventilation or cooling system powered from the energy store onthe towed vehicle at least during some extended periods of time duringwhich an engine of the towing-vehicle is off.

In some embodiments, the method further includes selectively controllingan operating mode of a battery management system, wherein in at leastone selectable mode, energy recovered using the drive axle in aregenerative braking mode is used to bring the energy store to asubstantially full state of charge, and wherein in at least anotherselectable mode, state of charge is managed to a dynamically varyinglevel based at least in part on uphill and downhill grades along currentor predicted route of travel.

In some embodiments, the selective control is provided from a controlinterface of a heating, ventilation or cooling system on the towingvehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and notlimitation with reference to the accompanying figures, in which likereferences generally indicate similar elements or features.

FIG. 1A depicts a bottom view of a hybrid suspension system, inaccordance with some embodiments;

FIG. 1B depicts a top view of the hybrid suspension system, inaccordance with some embodiments;

FIG. 1C depicts an exemplary tractor-trailer vehicle, including thehybrid suspension system, in accordance with some embodiments;

FIGS. 2A-2F illustrate a control system circuit, which may be housedwithin (or otherwise integrated with) the hybrid suspension system ofFIGS. 1A and 1B, in accordance with some embodiments;

FIG. 3 depicts an exemplary controller area network (CAN bus) that maybe used for communication of the various components of the controlsystem circuit of FIGS. 2A-2F, in accordance with some embodiments;

FIG. 4 is a functional block diagram of a hardware and/or softwarecontrol system, in accordance with some embodiments;

FIG. 5A is a flow diagram that illustrates a control strategy employedin certain equivalent consumption minimization strategy (ECMS) oradaptive ECMS-type controller designs that may be employed in a hybridsuspension system and/or a TTR hybrid system, in accordance with someembodiments;

FIG. 5B is a flow diagram that illustrates a method for controlling ahybrid suspension system, in accordance with some embodiments;

FIG. 5C is a flow diagram that illustrates an additional aspect of amethod such as illustrated in FIG. 5B for controlling the hybridsuspension system, in accordance with some embodiments;

FIG. 6 is an exemplary functional block diagram illustrating control ofan on-trailer hybrid suspension system, in accordance with someembodiments; and

FIG. 7 illustrates an embodiment of an exemplary computer systemsuitable for implementing various aspects of the control system andmethods of FIGS. 5A-5C, in accordance with some embodiments.

Skilled artisans will appreciate that elements or features in thefigures are illustrated for simplicity and clarity and have notnecessarily been drawn to scale. For example, the dimensions orprominence of some of the illustrated elements or features may beexaggerated relative to other elements or features in an effort to helpto improve understanding of certain embodiments of the presentinvention(s).

DESCRIPTION

The present application describes a variety of embodiments, or examples,for implementing different features of the provided subject matter.Specific examples of components and arrangements are described below tosimplify the present disclosure. These are, of course, merely examplesand are not intended to be limiting. In addition, the present disclosuremay repeat reference numerals and/or letters in the various examples.This repetition is for the purpose of simplicity and clarity and doesnot in itself dictate a relationship between the various embodimentsand/or configurations discussed.

In particular, the present disclosure describes designs and techniquesfor providing an energy management system and related methods in thecontext of systems and components typical in the heavy truckingindustry. Some embodiments of the present invention(s) provide ahybridized suspension assembly (e.g., an electrically driven axle, powersource, controller, etc. that may be integrated with suspensioncomponents) affixed (or suitable for affixing) underneath a vehicle(e.g., a truck, tractor unit, trailer, tractor-trailer or tandemconfiguration, etc.) as a replacement to a passive suspension assembly.In various non-limiting example configurations, a hybridized suspensionassembly can be part of a trailer that may be towed by a poweredvehicle, such as a fuel-consuming tractor unit.

As described in more detail below, a hybridized suspension assembly isbut one realization in which an electrically driven axle operateslargely independently of the fuel-fed engine and primary drivetrain of apowered vehicle and is configured to operate in a power assist,regeneration, and passive modes to supplement motive/braking forces andtorques applied by the primary drivetrain and/or in braking. In general,one or more electrically driven axles may supplement motive/brakingforces and torques under control of a controller (or controllers) thatdoes not itself (or do not themselves) control the fuel-fed engine andprimary drivetrain. Instead, a control strategy implemented by anelectric drive controller seeks to follow and supplement the motiveinputs of the fuel-fed engine and primary drivetrain using operatingparameters that are observable (e.g., via CANbus or SAE J1939 typeinterfaces), kinematics that are sensed and/or states that may becomputationally estimated based on either or both of the foregoing. Insome embodiments, based on such observed, sensed or estimated parametersor states, the electric drive controller applies an equivalentconsumption minimization strategy (ECMS) or adaptive ECMS type controlstrategy to modulate the motive force or torque provided, at theelectrically driven axle(s), as a supplement to that independentlyapplied using the fuel-fed engine and primary drivetrain of the poweredvehicle.

By supplementing the fuel-fed engine and primary drivetrain of thepowered vehicle, some embodiments of the present invention(s) seek tosimultaneously optimize fuel consumption of the powered vehicle, energyconsumption of the hybrid suspension assembly, and/or state of charge(SOC) of on-board batteries or other energy stores. In some cases, suchas during stopovers, embodiments of the present disclosure allow thefuel-fed engine to shut down rather than idle. In some cases, energyconsumption management strategies may take into account a desired SOC atscheduled, mandated or predicted stopovers. Among other advantages,embodiments disclosed herein provide for a significant reduction in fuelconsumption (e.g., an average of about 30%), a built-in auxiliary powerunit (APU), enhanced stability control, improved trailer dynamics, and ahost of other benefits, at least some of which are described in moredetail below.

Referring now to FIGS. 1A-1C, illustrated therein is a hybrid suspensionsystem 100. As used herein, the term hybrid suspension system is meantto convey to a person of skill in the art having benefit of the presentdisclosure, a range of embodiments in which some or all components of asupplemental electrically driven axle, often (though not necessarily)including a controller, a power source, brake line sensors, CANbus orSAE J1939 type interfaces, sensor packages, off-vehicle radio frequency(RF) communications and/or geopositioning interfaces, etc. are packagedor integratable with components that mechanically interface one or moreaxles and wheels to the frame or structure of a vehicle and whichtypically operate (or interface with additional components) to absorb ordampen mechanical perturbuations and maintain tire contact with aroadway during travel thereover. In some though not all embodiments, ahybrid suspension system can take on the form or character of anassembly commonly referred to in the U.S. trucking industry as a sliderbox. In some though not all embodiments, a hybrid suspension system maybe or become more intregral with a vehicle frame and need not have themodular or fore/aft adjustability commonly associated with slider boxes.

Likewise, the “hybrid” or hybridizing character of a hybrid suspensionsystem, such as hybrid suspension system 100, will be understood bypersons of skill in the art having benefit of the present disclosure inthe context of its role in hybridizing the sources of motive force ortorque available in an over-the-road vehicle configuration that includesit. Accordingly, a hybrid suspension system including anelectrically-driven axle and controller for coordinating itssupplementation of motive force or torques need not, and typically doesnot itself include, the additional drive axles driven by the fuel fedengine to which it contributes a hybrid or hybridizing source of motiveforce or torque. Thus, the tractor-trailer configuration (160)illustrated in FIG. 1C is exemplary and will be understood to include ahybrid suspension system, notwithstanding the ability of the trailer(170) to be decoupled from tractor units (e.g., tractor unit 165) thatprovide the fuel fed engine and primary drivetrain to which it acts as asupplement. Correspondingly, a vehicle such as a heavy truck having asingle frame or operable as or with tandem trailers (not specificallyshown in FIG. 1C) will be understood to be amenable to inclusion of oneor more hybrid suspension systems.

In view of the foregoing, and without limitation, hybrid suspensionsystem-type embodiments are now described with respect to specificexamples.

Hybrid Suspension System

As described in more detail below, the hybrid suspension system 100 mayinclude a frame 110, a suspension, one or more drive axles (e.g., suchas a drive axle 120), at least one electric motor-generator (e.g., suchas an electric-motor generator 130) coupled to the at least one or moredrive axles, an energy storage system (e.g., such as a battery array140), and a controller (e.g., such as a control system 150). Inaccordance with at least some embodiments, the hybrid suspension system100 is configured for attachment beneath a trailer. As used herein, theterm “trailer” is used to refer to an unpowered vehicle towed by apowered vehicle. In some cases, the trailer may include a semi-trailercoupled to and towed by a truck or tractor (e.g., a powered towingvehicle). By way of example, FIG. 1C illustrates a tractor-trailervehicle 160 that includes a tractor 165 coupled to and operable to tow atrailer 170. In particular, and in accordance with embodiments of thepresent disclosure, the hybrid suspension system 100 is coupledunderneath the trailer 170, as a replacement to a passive suspensionassembly, as discussed in more detail below. For purposes of thisdiscussion, the tractor 165 may be referred to generally as a “poweredtowing vehicle” or simply as a “powered vehicle”.

To be sure, embodiments of the present disclosure may equally be appliedto other types of trailers (e.g., utility trailer, boat trailer, traveltrailer, livestock trailer, bicycle trailer, motorcycle trailer, agooseneck trailer, flat trailer, tank trailer, farm trailer, or othertype of unpowered trailer) towed by other types of powered towingvehicles (e.g., pickup trucks, automobiles, motorcycles, bicycles,buses, or other type of powered vehicle), without departing from thescope of this disclosure. Likewise, although components are introducedand described in the context of an exemplary suspension assembly for atrailer, persons of skill in the art having benefit of the presentdisclosure will appreciate adaptations of configurations and componentsintroduced in the exemplary trailer context to supplemental electricallydriven axle applications such as affixed (or suitable for affixing)underneath a vehicle (e.g., a truck, tractor unit, trailer,tractor-trailer or tandem configuration, etc.).

Vehicles may utilize a variety of technologies and fuel types such asdiesel, gasoline, propane, biodiesel, ethanol (E85), compressed naturalgas (CNG), hydrogen internal combustion engine (ICE), homogeneous chargecompression ignition (HCCI) engine, hydrogen fuel cell, hybrid electric,plug-in hybrid, battery electric, and/or other type of fuel/technology.Regardless of the type of technology and/or fuel type, the poweredtowing vehicle (or more generally the fuel-fed engine of a poweredvehicle) may have a particular fuel efficiency. As described below, andamong other advantages, embodiments of the present disclosure providefor improved fuel efficiency of the powered vehicle, as described inmore detail herein. More generally, and in accordance with variousembodiments, the hybrid suspension system 100 described herein isconfigured (or may be adapted) for use with any type of trailer orpowered vehicle.

In addition, the hybrid suspension system 100 is configured to operatelargely independently of the fuel-fed engine and primary drivetrain of apowered vehicle and, in some cases, autonomously from the engine anddrivetrain controls of the powered vehicle. As used herein, “autonomous”operation of the hybrid suspension system 100 is terminology used todescribe an ability of the hybrid suspension system 100 to operatewithout commands or signals from the powered towing vehicle, toindependently gain information about itself and the environment, and tomake decisions and/or perform various functions based on one or morealgorithms stored in the controller, as described in more detail below.“Autonomous” operation does not preclude observation or estimation ofcertain parameters or states of a powered vehicle's fuel-fed engine orprimary drivetrain; however, in some embodiments of the presentinvention(s), electrically driven axles are not directly controlled byan engine control module (ECM) of the powered vehicle and, even whereECMS or adaptive ECMS-type control strategies are employed, no singlecontroller manages control inputs to both the supplemental electricallydriven axle(s) and the primary fuel-fed engine and drivetrain.

A trailer, as typically an unpowered vehicle, includes one or morepassive axles. By way of example, embodiments of the present disclosureprovide for replacement of the one or more passive trailer axles withone or more powered axles. For example, in at least some embodiments,the hybrid suspension system 100 may replace a passive tandem axle witha powered tandem axle, as shown in the example of FIG. 1C. In accordancewith some embodiments the present invention(s), the hybrid suspensionsystem 100 can be configured to provide, in a first mode of operation, amotive rotational force (e.g., by an electric motor-generator coupled toa drive axle) to propel the hybrid suspension system 100, and thus thetrailer under which is attached, thereby providing an assistive motiveforce to the powered towing vehicle. Thus, in some examples, the firstmode of operation may be referred to as a “power assist mode.”Additionally, in some embodiments, the hybrid suspension system 100 isconfigured to provide, in a second mode of operation, a regenerativebraking force (e.g., by the electric motor-generator coupled to thedrive axle) that charges an energy storage system (e.g., the batteryarray). Thus, in some examples, the second mode of operation may bereferred to as a “regeneration mode.” In some examples, the hybridsuspension system 100 is further configured to provide, in a third modeof operation, neither motive rotational nor regenerative braking forcesuch that the trailer and the attached hybrid suspension system 100 aresolely propelled by the powered towing vehicle to which the trailer iscoupled. Thus, in some examples, the third mode of operation may bereferred to as a “passive mode.”

In providing powered axle(s) to the trailer (e.g., by the hybridsuspension system 100), embodiments of the present disclosure result ina significant reduction in both fuel consumption and any associatedvehicle emissions, and thus a concurrent improvement in fuel efficiency,of the powered towing vehicle. In addition, various embodiments mayprovide for improved vehicle acceleration, vehicle stability, and energyrecapture (e.g., via regenerative braking) that may be used for avariety of different purposes. For example, embodiments disclosed hereinmay use the recaptured energy to apply the motive rotational force usingthe electric motor-generator and/or provide on-trailer power that may beused for powering a lift gate, a refrigeration unit, a heatingventilation and air conditioning (HVAC) system, pumps, lighting,communications systems, and/or providing an auxiliary power unit (APU),among others. It is noted that the above advantages and applications aremerely exemplary, and additional advantages and applications will becomeapparent to those skilled in the art upon review of this disclosure.

Referring again to FIG. 1A, illustrated therein is a bottom view of anexemplary hybrid suspension system 100 which shows the frame 110, thedrive axle 120, a passive axle 125, and wheels/tires 135 coupled to endsof each of the drive axle 120 and the passive axle 125. In someembodiments, the electric motor-generator 130 is coupled to the driveaxle 120 by way of a differential 115, thereby allowing the electricmotor generator 130 to provide the motive rotational force in the firstmode of operation, and to charge the energy storage system (e.g., thebattery array) by regenerative braking in the second mode of operation.Note that in some embodiments, components such as the electric motorgenerator, gearing and any differential may be more or less integrallydefined, e.g., within a single assembly or as a collection ofmechanically coupled components, to provide an electrically-driven axle.While shown as having one drive axle and one passive axle, in someembodiments, the hybrid suspension system 100 may have any number ofaxles, two or more drive axles, as well as multiple electric-motorgenerators on each drive axle. In addition, axles of the hybridsuspension system (e.g., the drive axle 120 and the passive axle 125)may be coupled to the frame 110 by a leaf spring suspension, an airsuspension, a fixed suspension, a sliding suspension, or otherappropriate suspension. In some embodiments, the wheels/tires 135coupled to ends of one or both of the drive axle 120 and the passiveaxle 125 may be further coupled to a steering system (e.g., such as amanual or power steering system), thereby providing for steering of thehybrid suspension system 100 in a desired direction.

With reference to FIG. 1B, illustrated therein is a top view of thehybrid suspension system 100 showing the battery array 140 and thecontrol system 150. In various embodiments, the battery array 140 andthe control system 150 may be coupled to each other by an electricalcoupling 145. In addition, the electric motor-generator 130 may becoupled to the control system 150 and to the battery array 140, therebyproviding for energy transfer between the battery array 140 and theelectric motor-generator 130. In various examples, the battery array 140may include one or more of an energy dense battery and a power densebattery. For example, in some embodiments, the battery array 140 mayinclude one or more of a nickel metal hydride (NiMH) battery, a lithiumion (Li-ion) battery, a lithium titanium oxide (LTO) battery, a nickelmanganese cobalt (NMC) battery, a supercapacitor, a lead-acid battery,or other type of energy dense and/or power dense battery.

Control System Architecture and Components

As discussed above, the hybrid suspension system 100 is configured tooperate autonomously and in at least three modes of operation: (i) apower assist mode, (ii) a regeneration mode, and (iii) a passive mode.In particular, and in various embodiments, the hybrid suspension system100 is operated in one of these three modes by way of the control system150 (e.g., in conjunction with suitable program code, as discussedbelow). Various aspects of the control system 150, including systemarchitecture and exemplary components, are described in more detailbelow with reference to FIGS. 2A-2F, 3, and 4.

Referring first to FIGS. 2A-2F, illustrated therein is a control systemcircuit 200 that may be housed within the control system 150. It isnoted that the control system circuit 200, and the components shown anddescribed herein are merely exemplary, and other components and/orcircuit architecture may be used without departing from the scope of thethis disclosure. FIG. 2A shows an AC motor controller 202, which may beused to actuate the electric motor-generator 130. By way of example, andin some cases, the AC motor controller 202 may include a Gen4 Size 8controller manufactured by Sevcon USA, Inc. of Southborough, Mass. Insome embodiments, the AC motor controller 202 is coupled to an AC motorcontroller relay 238 (FIG. 2D). As described below with reference toFIG. 3, the AC motor controller 202 may communicate with othercomponents of the control system circuit 200 by way of a controller areanetwork (CAN bus). In some embodiments, a CANbus or SAE J1939 interfacemay be provided to other systems. FIG. 2B shows an electricmotor-generator 204, which may be the electric motor-generator 130discussed above, and which may be actuated by the AC motor controller202. In some examples, the electric-motor generator 204 may include anelectric motor-generator manufactured by Remy International, Inc. ofPendleton, Ind. FIG. 2C illustrates a water pump 206 coupled to a waterpump relay 218, a water fan 208 coupled to a wafer fan relay 220, an oilpump 210 coupled to an oil pump relay 222, an oil fan 212 coupled to anoil fan relay 224, and a ground bus bar 214. Each of the water pump 206,the water fan 208, the oil pump 210, and the oil fan 212 may be coupledto a voltage supply 216 (and thus enabled) by way of their respectiverelay, where the relays are coupled to and actuated by a master controlunit 228 (FIG. 2D). In addition, the ground bus bar 214 may be coupledto a ground plane 226 (FIG. 2D), and each of the water pump 206, thewater fan 208, the oil pump 210, and the oil fan 212 may be coupled tothe ground plane 226 by way of the ground bus bar 214.

In addition to the master control unit 228, FIG. 2D illustrates a DC-DCpower supply 230 coupled to a DC-DC control relay 236, a brake pressuresensor 232 coupled to the master control unit 228, a ground faultdetector (GFD) 234 coupled to a battery management system (BMS)/GFDrelay 240, and the AC motor controller relay 238. The DC-DC power supply230 may be coupled to the voltage supply 216 (and thus enabled) by wayof the DC-DC control relay 236, which is coupled to and actuated by amaster control unit 228. Similarly, the GFD 234 and a “Key On−” input ofa BMS 242 (FIG. 2E) may be coupled to the voltage supply 216 by way ofthe BMS/GFD relay 240, which is also coupled to and actuated by themaster control unit 228. The AC motor controller 202 may also be coupledto the voltage supply 216 (and thus enabled) by way of the AC motorcontroller relay 238, which is also coupled to and actuated by themaster control unit 228. In various embodiments, the DC-DC power supply230 and the master control unit 228 may communicate with othercomponents of the control system circuit 200 by way of the CAN bus, asdiscussed below. FIG. 2E shows the “Key On−” input of a BMS 242 coupledto the BMS/GFD relay 240, as discussed above. In addition, a “Key On+”input of the BMS 242 may be coupled directly to the voltage supply 216,as shown in FIG. 2F. In some embodiments, the BMS 242 may alsocommunicate with other components of the control system circuit 200 byway of the CAN bus, as discussed below.

Referring specifically to FIG. 2F, illustrated therein is a compressor244 coupled to a cooling relay 248, an attitude and heading referencesystem (AHRS) 246 coupled to an AHRS relay 252, and an optional inverterrelay 250. By way of example, the compressor may include a variablefrequency drive (VFD) or variable speed drive (VSD) compressor. Thecompressor 244 may be coupled to the voltage supply 216 (and thusenabled) by way of the cooling relay 248, which is coupled to andactuated by a master control unit 228. Similarly, the AHRS 246 may becoupled to the voltage supply 216 (and thus enabled) by way of the AHRSrelay 252, which is coupled to and actuated by a master control unit228. In some embodiments, the AHRS 246 may communicate with othercomponents of the control system circuit 200 by way of the CAN bus, asdiscussed below. In various embodiments, the control system circuit 200further includes an inverter, as shown below in FIG. 4, that may becoupled to the DC-DC power supply 230 and which may be optionallyenabled/disabled using the inverter relay 250 by the master control unit228. Moreover, in various embodiments, the inverter is coupled to theelectric motor-generator 204 to provide power to, or receive power from,the electric motor-generator 204. It is again noted that the descriptionof the control system circuit 200 is merely exemplary, and otheraspects, advantages, and useful components will be evident to thoseskilled in the art, without departing from the scope of this disclosure.For example, in various embodiments, the control system circuit 200 mayalso include one or more of a fuse and relay module, a 12 volt battery,a fuse block, one or more battery disconnect switches, one or moreelectrical contactors, a pre-charge resistor, and/or other components asknown in the art.

With reference now to FIG. 3, illustrated therein is a controller areanetwork (CAN bus) 300 used for communication of the various componentsof the control system circuit 200 with one another. Generally, a CAN busis a vehicle bus standard designed to allow microcontrollers and otherdevices such as electronic control units (ECUs), sensors, actuators, andother electronic components, to communicate with each other inapplications without a host computer. In various embodiments, CAN buscommunications operate according to a message-based protocol.Additionally, CAN bus communications provide a multi-master serial busstandard for connecting the various electronic components (e.g., ECUs,sensors, actuators, etc.), where each of the electronic components maybe referred to as a ‘node’. In various cases, a CAN bus node may rangein complexity, for example from a simple input/output (I/O) device,sensors, actuators, up to an embedded computer with a CAN bus interface.In addition, in some embodiments, a CAN bus node may be a gateway, forexample, that allows a computer to communicate over a USB or Ethernetport to the various electronic components on the CAN network. In variousembodiments, CAN bus nodes are connected to each other through a twowire bus (e.g., such as a 120Ω nominal twisted pair) and may beterminated at each end by 120Ω resistors.

In particular, the CAN bus 300 is illustrated as a linear bus terminatedat each end by 120Ω resistors. In some embodiments, the CAN bus 300includes an ISO 11898-2 high speed CAN bus (e.g., up to 1 Mb/s). By wayof example, the CAN bus 300 is shown as including as nodes, for example,the AC motor controller 202, the BMS 242, the AHRS 246 (sensor), themaster control unit 228, the DC-DC power supply 230 (actuator), andtelematics unit 302 (smart sensor). In some embodiments, the telematicsunit 302 may include a global positioning system (GPS), an automaticvehicle location (AVL) system, a mobile resource management (MRM)system, a wireless communications system, a radio frequencyidentification (RFID) system, a cellular communications system, and/orother telematics systems. In some embodiments, the telematics unit 302may also include the AHRS 246. In accordance with various embodiments,at least some of the sensors, actuators, and other electronic componentswhich are not included (e.g., shown in FIG. 3) as CAN bus nodes, maythemselves be coupled to the CAN bus 300 by way of one or more of theCAN bus nodes. For example, a voltage meter (sensor), a current meter(sensor), and one or more electrical contactors (actuators) may becoupled to the CAN bus 300 by way of the BMS 242. Similarly, the waterpump 206 (actuator), the water fan 208 (actuator), the oil pump 210(actuator), the oil fan 212 (actuator), the GFD 234 (sensor), aninverter, the brake pressure sensor 232, a trailer weight sensor, aswell as other actuators, sensors, and/or electronic components may becoupled to the CAN bus 300 by way of the master control unit 228. Insome examples, the electric motor-generator 204 (actuator) is coupled tothe CAN bus 300 by way of the AC motor controller 202. In someembodiments, a CANbus or SAE J1939 interface may be provided to othersystems, such as those of a powered vehicle to facilitate read-typeaccess to operating parameters or otherwise observable states of systemsthereof.

Referring now to FIG. 4, illustrated therein is control system diagram400 which provides further detail regarding connections and/orcommunication between and among the various control system components,some of which have been shown and described above (e.g., as part of thecontrol system circuit 200 and/or the CAN bus 300). By way of example,the control system diagram 400 shows that the master control unit 228 isconfigured to operate as a Master′ controller, while each of the BMS 242and the AC motor controller 202 are configured to operate as ‘Slave’controllers and are thereby under control of the master control unit228. In some embodiments, and as illustrated in the control systemdiagram 400, the master control unit 228 provides for control (e.g.,actuation of and/or receipt of a sensor output) for each of the waterpump 206, the water fan 208, the oil pump 210, the oil fan 212, atrailer weight sensor 408, the DC-DC power supply 230, an inverter 412,the AHRS 246, a telematics unit 410, the GFD 234, and the brake pressuresensor 232. Additionally, the BMS 242 provides for control (e.g.,actuation of and/or receipt of a sensor output) for each of a voltagemeter 402, a current meter 404, and one or more electrical contactors406. In some embodiments, the AC motor controller 202 provides forcontrol (e.g., actuation) of the electric motor-generator 204, asdiscussed above.

Control Methods, Generally

Various aspects of the hybrid suspension system 100 have been describedabove, including aspects of the control system architecture and relatedcomponents. It particular, it has been noted that the hybrid suspensionsystem 100 is operated, by way of the control system 150 and suitableprogram code, in at least three modes of operation: (i) a power assistmode, (ii) a regeneration mode, and (iii) a passive mode. In at leastsome embodiments, the program code used to operate the control system150 may reside on a memory storage device within the master control unit228 (FIG. 2D). In addition, the master control unit 228 may include amicroprocessor and/or microcontroller operable to execute one or moresequences of instructions contained in the memory storage device, forexample, to perform the various methods described herein. In some cases,one or more of the memory storage, microprocessor, and/ormicrocontroller may reside elsewhere within the hybrid suspension system100, or even at a remote location that is in communication with thehybrid suspension system 100. In some embodiments, a general purposecomputer system (e.g., as described below with reference to FIG. 7) maybe used to implement one or more aspects of the methods describedherein.

A variety of control systems designs are contemplated and will beappreciated by persons of skill in the art having benefit of the presentdisclosure. For example, in some embodiments, control system 150 isprogrammed to apply an equivalent consumption minimization strategy(ECMS) or adaptive ECMS type control strategy to modulate the motiveforce or torque provided, at an electrically driven axle(s), as asupplement to motive force or torques that control system 150 estimatesare independently applied using the fuel-fed engine and primarydrivetrain of the powered vehicle. In some embodiments, control system150 is programmed to operate in conjunction with an altitude and headingreference system (AHRS). Exemplary ECMS type and AHRS type controlstrategies are now described.

FIG. 5A is a flow diagram that illustrates computations of a controllerthat applies an equivalent consumption minimization strategy (ECMS) tothe hybrid suspension system 100 design previously explained.Interactions of a programmed controller 228 with battery array 140, witha vehicle CANbus (for retrieval of operating conditions indicative ofcurrent torque delivered by fuel-fed engine through the primary drivetrain and current gear ratios of that primary drivetrain), andultimately with electric motor-generator 130 via any local controller(e.g., sevcon controller 202) are all illustrated.

Based on the current SOC for battery array 140, an array of possibleoptions for amperage discharge and charge values are calculated. Thesepossibilities are converted to kW power as potential battery powerdischarge and charge possibilities. Battery inefficiencies and motorcontroller inefficiencies are considered along with possible electricdrivetrain gear ratios to arrive at the corresponding potential electricmotor torques that can be applied and resultant wheel torques which canbe applied to the vehicle using electric motor-generator 130. Using thebattery power discharge and charge possibilities, a corresponding dieselusage table is calculated using a lookup table that stores values forbattery power equivalence based on various SOC conditions of batteryarray 140.

Based on current operating parameters retrieved from the vehicle CANbus(e.g., engine torque and current gear ratios in the primary drivetrain)or optionally based on estimates calculated based on a high-precisioninertial measurement unit (IMU) effective torque delivered at vehiclewheels by the fuel-fed engine and the primary drivetrain is calculatedor otherwise computationally estimated at controller 228. Potentialsupplemental torques that can be provided at wheels driven (or drivable)by electric motor-generator 130 are blended with those calculated orestimated for vehicle wheels driven by the fuel-fed engine and primarydrivetrain in a calculation that back-calculates where the variousadditional supplemental torques would place the vehicle's engine. Then,based on these new values for the fuel-fed engine and primarydrivetrain, a vehicle fuel usage consumption table is updated and, inturn, combined with (computationally summed) a charge/fuel usage tablefor electric motor-generator 130. Based on the current SOC, SOC targets,and SOC hysteresis, a minimum index value from the discharge fuel usagetable or the charge fuel usage table is used. A motor torque at thisindex is retrieved from the motor torque possibilities table, and thistorque demand is sent to electric motor-generator 130 via any localcontroller (e.g., sevcon controller 202) to be applied as supplementaltorque via the electric drivetrain in a TTR hybrid configuration.

Turning to FIG. 5B, illustrated therein is a method 500 of controlling ahybrid suspension system, such as the hybrid suspension system 100described above with reference to FIGS. 1A-1C. Generally, and in someembodiments, the method 500 provides a method for determining how muchtorque should be provided by the hybrid suspension system 100, and assuch in which mode to operate the hybrid suspension system 100 (e.g.,power assist, regeneration, or passive), in order to keep the hybridsuspension system 100, a trailer to which the hybrid suspension system100 is coupled, and a powered vehicle towing the trailer, moving alongtheir current trajectory at a substantially constant speed. Among otheradvantages, embodiments of the method 500 provide for a reduction inboth fuel consumption and any associated vehicle emissions, and thus aconcurrent improvement in fuel efficiency, of a powered vehicle towingthe trailer, as well as improved vehicle acceleration, vehiclestability, and energy recapture (e.g., via regenerative braking).

It is also noted that while performing the method 500, aspects of thepresent disclosure may additionally receive data from, send data to,actuate, other otherwise interact with various components of the controlsystem circuit 200 and the CAN bus 300, described above. Thus, one ormore aspects discussed above may also apply to the method 500. Moreover,additional process steps may be implemented before, during, and afterthe method 500, and some process steps described above may be replacedor eliminated in accordance with various embodiments of the method 500.

Referring now to the method 500, the method 500 begins at block 502where trailer data is received from one or more on-board sensors. Asused herein, the term “on-board sensors” may be used to describe sensorsthat are coupled to or part of the hybrid suspension system 100, sensorsthat are coupled to or part of a trailer to which the hybrid suspensionsystem 100 is attached, as well as remote sensors that may communicate(e.g., by way of cellular, wireless, RF, satellite, or other suchcommunication) data to a receiver or transceiver that is coupled to orpart of the hybrid suspension system 100 or the trailer. In someembodiments, the described sensors may be coupled to or part of thetractor 165 to which the trailer is coupled. In various embodiments, thesensors may include one or more of a brake pressure sensor (e.g., suchas the brake pressure sensor 232), an altitude and heading referencesystem (e.g., such as the AHRS 246), one or more smart sensors (e.g.,such as the telematics unit 302) which may include a global positioningsystem as well as other smart sensors and/or telematics systems asdescribed above, a trailer weight sensor which may include an air bagpressure sensor (e.g., provided in a suspension assembly of the towedvehicle) or other type of weight sensor, a speed sensor, a gyroscope, anaccelerometer, a magnetometer, a lateral acceleration sensor, a torquesensor, an inclinometer, and/or other suitable sensor. In variousembodiments, the sensed trailer data is sent to the master control unit228 for further processing. For example, in some embodiments, thereceived trailer data (e.g., the sensor output) may be filtered tosmooth the sensor data and thereby mitigate anomalous sensor values. Insome cases, such filtering and smoothing may be accomplished usingmoving averages and Kalman filters, although other smoothing and/orfiltering techniques may also be used. In at least some examples, anestimated braking torque is obtained from the brake pressure sensor, anestimated weight of the trailer is obtained from the air bag pressuresensor, and a trailer acceleration and roadway incline are both obtainedfrom the AHRS.

The method 500 then proceeds to block 504 where based at least in parton the trailer data, a total estimated torque is computed. In someembodiments, the total estimated torque includes an estimated torque tomaintain movement of the hybrid suspension system 100, and a trailer towhich the hybrid suspension system 100 is coupled, along their currenttrajectory at a substantially constant speed. In embodiments when thetrailer is at least partially towed by a powered vehicle, the totalestimated torque further includes an estimated torque to maintainmovement of the hybrid suspension system 100, the coupled trailer, andthe powered vehicle, along their current trajectory at a substantiallyconstant speed. For purposes of this discussion, the hybrid suspensionsystem 100, the coupled trailer, and the powered vehicle may becollectively referred to as “a hybrid trailer vehicle system (HTVS)”.Thus, in some embodiments, the tractor-trailer vehicle 160 of FIG. 1Cmay be referred to as an HVTS.

In an embodiment of block 504, computing the total estimated torque mayinclude computing one or more of a plurality of forces acting on theHTVS. For example, computing the total estimated torque may includecomputing a driver input torque (e.g., throttle/braking of the poweredvehicle), an air drag torque, a road drag torque, a road grade torque,and an acceleration torque, among others. In some embodiments, the airdrag torque and the road drag torque may be dependent on a speed atwhich the HTVS is traveling. In some cases, the road grade torque may bedependent on an incline/decline of a roadway on which the HTVS istraveling. By way of example, the driver of the powered vehicle of theHTVS may actuate an air brake system. In such cases, embodiments of thepresent disclosure may utilize an air brake pressure to calculate abraking torque component of the total estimated torque. In someembodiments, the driver input torque may be substantially equal to a sumof the air drag torque, the road drag torque, the road grade torque, andthe acceleration torque. In various embodiments, the total estimatedtorque computed at block 504 may include a currently-applied (e.g.,instantaneous) HTVS torque. Based in part on the total estimated torqueand an estimate and/or prediction of a driver-applied torque, asdiscussed in more detail below, a specified torque may be applied by wayof the hybrid suspension system 100 to one or more trailer axles.Moreover, in some embodiments and based in part on the total estimatedtorque and an estimate and/or prediction of a driver-applied torque, aspecified torque may be applied by way of the hybrid suspension system100, as described below.

The method 500 then proceeds to block 506 where a torque applied by apowered vehicle towing the trailer is computationally estimated (e.g.,by the control system 150). Stated another way, in embodiments of block506, a torque applied by a driver of the powered vehicle (e.g., byapplying throttle or braking) is estimated, for example, as a result ofthe hybrid suspension system 100 being autonomous from the poweredvehicle and thus not having direct feedback regarding driver inputs(e.g., throttle/braking). In some embodiments, the driver-applied torquemay also be predicted. Thus, in some examples, a currently-appliedtorque may be estimated and a subsequently applied torque may bepredicted. In some embodiments, the estimated and/or predicteddriver-applied torque may be based on a plurality of factors such aspast driver behavior, current driver behavior, road conditions, trafficconditions, weather conditions, and/or a roadway grade (e.g., roadincline or decline). As used herein, the term “driver behavior” may beused to describe a driver's operation of the powered vehicle, forexample, including application of throttle, braking, steering, as wellas other driver-controlled actions. Additionally, and in variousembodiments, at least some of the factors used to estimate and/orpredict the driver-applied torque may include data received from one ormore of the on-board sensors, described above, including GPS orinclinometer data that may be used to determine a present roadway gradeand/or predict an upcoming roadway grade. For example, if the upcomingroadway grade includes a positive grade (e.g., an incline), the drivermay in some embodiments be expected to apply additional throttle. Insome cases, if the upcoming roadway grade includes a negative grade(e.g., a decline), the driver may in some embodiments be expected toapply the brakes (e.g., of the powered vehicle). In some embodiments, ifthe upcoming roadway grade is substantially flat, the driver may in someembodiments be expected to neither apply additional throttle nor applythe brakes. In some examples, at least some of the factors used toestimate and/or predict the applied torque may further include trafficdata, weather data, road data, or other similar data. Similarly, if theupcoming roadway includes heavy traffic, poor road conditions (e.g., potholes, unpaved sections, etc.), or if weather has caused hazardousdriving conditions (e.g., rain, flooding, strong crosswinds, etc.), thedriver may in some embodiments be expected to apply the brakes. Thus, inaccordance with some embodiments, knowledge of an upcoming roadwaygrade, combined with a plurality of other data (e.g., traffic, weather,road data) and the driver's current and/or past behavior may be used toestimate and/or predict the driver-applied torque. It will be understoodthat the driver behaviors discussed above, with respect to roadway gradeand road/weather conditions, are merely exemplary. Various otherbehaviors (e.g., apply throttle during a negative grade or apply brakesduring a positive grade) are possible as well, without departing fromthe scope of the present disclosure.

The method 500 then proceeds to block 508 where based at least in parton the estimated and/or predicted torque (block 506) and the totalestimated torque (block 504), a specified trailer torque is computed andapplied to one or more of the trailer axles. In particular, thespecified trailer torque is applied to the one or more of the traileraxles by way of the hybrid suspension system 100, as described herein.Additionally, in an embodiment of block 508, the hybrid suspensionsystem 100 is operated in the appropriate one of the at least threemodes of operation (e.g., power assist, regeneration, or passive) inorder to provide the specified trailer torque. In some embodiments, thespecified trailer torque is computed, at least in part, by utilizing theestimated and/or predicted driver-applied torque in an energyoptimization algorithm that utilizes an equivalent consumptionminimization strategy (ECMS) to simultaneously optimize the fuelconsumption of the powered vehicle and the energy usage (e.g., batterycharge) of the hybrid suspension system 100.

An aspect of the energy optimization algorithm is illustrated in moredetail in FIG. 5C, which provides a method 550. In some embodiments, themethod 550 may be performed as part of, or in addition to, the method500. For example, in some cases, the method 550 may be performed as partof block 508 of the method 500, where the specified torque is computedand applied to the one or more trailer axles. By way of example, themethod 550 begins at block 552 where a first plurality of torques thatmay be applied by the powered vehicle, and a second plurality of torquesthat may be applied at the trailer (e.g., applied by the electricmotor-generator), are determined. In some embodiments, the firstplurality of torques may include a range of torque values which thepowered towing vehicle is capable of providing (e.g., by way of afuel-consuming engine, an electric motor, or other means of providing amotive force). Similarly, and in some embodiments, the second pluralityof torques may include a range of torque values which the hybridsuspension system 100 is capable of providing (e.g., by way of theenergy storage system and the electric motor-generator coupled to one ormore drive axles).

The method 550 then proceeds to block 554, where the first plurality oftorques is mapped onto a fuel usage map. For example, in someembodiments, a difference between the total estimated torque (block 504)and the second plurality of torques (e.g., each torque of a range ofpossible torque values which the hybrid suspension system 100 canprovide) is determined, where the difference provides a set ofcorresponding torque values that would be provided by the poweredvehicle (e.g., by the fuel-fed engine of the powered vehicle). Invarious embodiments, the set of corresponding torque values may be usedto generate a torque-to-fuel usage map for the powered vehicle. At block556 of the method 550, the second plurality of torques may be used tosimilarly generate a torque-to-energy usage map for the hybridsuspension system 100.

Thereafter, at block 558 of the method 550, an optimal combination of afirst torque from the first plurality of torques, and a second torquefrom the second plurality of torques, is selected. By way of example,and in an embodiment of block 558, the torque-to-energy usage map may beconverted to another torque-to-fuel usage map, so that mappings of thepowered vehicle and the hybrid suspension system 100 may be more readilycompared. In some cases, the torque-to-fuel usage map corresponding tothe hybrid suspension system 100 is subtracted from the torque-to-fuelusage map corresponding to the powered vehicle (e.g., the fuel-fedengine of the powered vehicle), thereby resulting in a combined poweredvehicle/hybrid suspension system usage map. Thereafter, in someembodiments, an optimal (e.g., minimum) fuel usage from the combinedusage map is determined, including a corresponding index value. In somecases, the corresponding index value is then used to select an optimaltorque value for the hybrid suspension system 100 from thetorque-to-energy usage map, and the optimal torque value for the hybridsuspension system 100 is applied, in an embodiment of both blocks 508and 558. In a more general sense, embodiments of the present disclosuremay be used to estimate a current torque demand of the HTVS. Using theestimated torque demand, at least some embodiments may be used todetermine an amount of fuel efficiency gain (e.g., of the poweredvehicle) and/or energy efficiency gain (e.g., of the hybrid suspensionsystem 100) that may be achieved by operating the hybrid suspensionsystem 100 in a particular mode, while applying a particular torque,thereby providing for selection of the optimal torque value for thehybrid suspension system 100.

With reference now to FIG. 6, illustrated therein is an exemplaryfunctional block diagram 600 for controlling the hybrid suspensionsystem 100, described above. In particular, the block diagram 600illustrates exemplary relationship, in at least some embodiments, amongvarious components of an HVTS, such as the tractor-trailer vehicle 160of FIG. 1C. Moreover, at least some aspects of the methods 500, 550,discussed above, may be better understood with reference to FIG. 6. Forexample, FIG. 6 illustrates the autonomous nature of the hybridsuspension system 100, where the hybrid suspension system 100 is able tooperate without direct commands or signals from the powered towingvehicle (e.g., such as the tractor 165), to independently gaininformation about itself, the trailer 170, and the environment (e.g., byway of the trailer sensing system), and to make decisions and/or performvarious functions based on one or more algorithms stored in the controlsystem 150.

The autonomous nature of the hybrid suspension system 100 is furtherexemplified, in at least some embodiments, by the functional blockdiagram 600 including two separate control loops, a hybrid suspensionsystem control loop 610 and a powered towing vehicle control loop 620.In the powered vehicle control loop 620, a driver 622 may apply athrottle 624 or a brake 626, which is then applied to the poweredvehicle (e.g., such as the tractor 165). In various embodiments, aresponse of the powered vehicle to the applied throttle 624/brake 626(e.g., acceleration/deceleration of the powered vehicle) may be providedas feedback to the driver 622, which the driver 622 may then furtherrespond to by applying additional throttle 624 or brake 626, or neitherthrottle 624/brake 626. In some examples, the powered vehicle may alsoprovide feedback (e.g., to the driver 622) via throttle 624/brake 626inputs.

Independent from the powered vehicle control loop 620, the hybridsuspension control loop 610 may operate in a substantially similarmanner to the methods 500, 550 described above. For example, in at leastsome embodiments, the hybrid suspension control system 150 may receivetrailer data from a trailer sensor system 602, which may include any ofthe one or more sensors discussed above. In some cases, the trailersensor system 602 may include the on-board sensors discussed above. Insome embodiments, the control system 150 may compute a total estimatedtorque and computationally estimate a torque applied by the poweredvehicle 165 (e.g., which may include estimating throttle and/orbraking). In some embodiments, based on the total estimated torque andthe computationally estimated torque of the powered vehicle, a specifiedtrailer torque may be computed and applied to the one or more traileraxles 120, by way of the electric motor-generator 130. In variousexamples, the driven one or more trailer axles 120 may provide feedbackto the control system 150, for further computation and application oftorque. In some cases, the one or more driven trailer axles 120 may alsoprovide feedback to the electric motor-generator 130. In at least someembodiments, the hybrid suspension system 100 may sense one or morepneumatic brake lines from the powered vehicle.

Control Methods, Examples and Further Discussion

The hybrid suspension system 100 may be used, for example together withaspects of the control methods described above, to operate in a varietyof different modes (e.g., power assist, regeneration, and passive modes)and thus perform a variety of different functions. In various examples,the hybrid suspension system 100 may be used to provide a power boost(e.g., to the HVTS) during acceleration and/or when going up an inclineby operating in the power assist mode, thereby depleting energy from theenergy storage system. In addition, the hybrid suspension system 100 mayreplenish that energy by operating in the regeneration mode (e.g., usingregenerative braking) when decelerating and/or when going down adecline. As discussed above, operation in one of the various modes maybe determined according to a variety of inputs and/or data (e.g., fromsensors, calculated values, etc.) such as discussed above. In variousexamples, the hybrid suspension system 100 and associated methods mayprovide, among other benefits, optimal application of power (e.g., asdiscussed in the example below), increased fuel mileage, decreased fuelemissions, and superior load stabilization. Of particular note,embodiments of the hybrid suspension system 100 described herein areconfigured to operate generally independently of the powered vehicle towhich the trailer may be attached. Thus, any type of powered vehicle mayhook up and tow a trailer, including the hybrid suspension system 100attached thereunder, and the hybrid suspension system 100 willautomatically adapt to the powered vehicle's behavior.

With respect to optimal application of power as discussed above, thereare scenarios in which battery power could be used most effectively at agiven time, for example, knowing that battery power may be (i)regenerated in the near future (e.g., based on an upcoming downhillroadway grade) or (ii) needed in the near future (e.g., based on anupcoming uphill roadway grade). Such information (e.g., regarding theupcoming roadway) may be gathered from GPS data, inclinometer data,and/or other sensor data as described above. In some embodiments, thehybrid suspension system 100 may alternatively and/or additionallyperiodically query a network server, or other remote sever/database, toprovide an upcoming roadway grade.

For purposes of illustration, consider an example where an HTVS istraveling along substantially flat terrain, while the battery array 140of the hybrid suspension system 100 is at about a 70% state of charge(SOC). Consider also that there is an extended downhill portion ofroadway coming up that would provide for regeneration about 40% SOC ofthe battery array 140 (e.g., while operating the hybrid suspensionsystem 100 in the regeneration mode). Absent knowledge of the upcomingextended downhill portion of the roadway, some embodiments may operatein the passive mode on the substantially flat terrain, while beginningto regenerate the battery array 140 once the HTVS reaches the extendeddownhill portion of roadway. In such cases, about 30% SOC may beregenerated before the battery array 140 is fully charged. Thus, thesystem may not be able to regenerate further, and about 10% SOC thatcould have been captured may be lost.

In some embodiments, the predictive road ability discussed hereinprovides knowledge of the upcoming extended downhill portion of roadway.As such, the hybrid suspension system 100 may autonomously engage thepower assist mode while traveling along the substantially flat terrain,such that about 10% SOC of the battery array 140 is used prior toreaching the extended downhill portion of roadway, thereby improvingfuel efficiency of the HTVS (e.g., while on the substantially flatterrain), while still regenerating about 30% SOC while traveling alongthe extended downhill portion. Such system operation, including thepredictive road ability, advantageously provides for both improved fuelefficiency of the HTVS efficient use of the battery array 140 (e.g., asit may be undesirable to have the battery array nearly full or nearlyempty when there is an opportunity to regenerate or provide powerassistance).

In another example, consider a case where the battery array 140 is atabout 10% SOC and the HTVS is traveling along substantially flatterrain. Consider also that an extended uphill portion of roadway iscoming up that would optimally be able to use about 20% SOC of thebattery array 140 (e.g., while operating the hybrid suspension system100 in the power assist mode). Once again, absent knowledge of theupcoming extended uphill portion of the roadway, some embodiments mayoperate in the passive mode on the substantially flat terrain, whilebeginning to use energy (e.g., operating in the power assist mode) oncethe HTVS reaches the extended uphill portion of the roadway. Thus, insuch an example, the battery array 140 may expend its 10% SOC before thehybrid suspension system 100 may not be able to assist further. Statedanother way, about 10% SOC that could have been effectively used by theHTVS while traveling along the extended uphill portion of the roadway isnot available.

As discussed above, the predictive road ability provides knowledge ofthe upcoming extended downhill portion of roadway. As such, the hybridsuspension system 100 may autonomously engage the regeneration modewhile traveling along the substantially flat terrain, such that about10% SOC of battery array 140 is regenerated, for a total of about 20%SOC, prior to reaching the extended uphill portion of the roadway. Whilethis may result in a temporary decrease in fuel efficiency, theefficiency gains afforded by operating the hybrid suspension system 100in the power assist mode for the duration of the extended uphill portionof the roadway (e.g., and optimally using the 20% SOC of the batteryarray 140) outweigh any potential efficiency reductions that may occurby regenerating on the substantially flat terrain.

In addition to using the various sensors, data, networking capabilities,etc. to determine whether the HTVS is traveling along substantially flatterrain, uphill, or downhill, embodiments of the present disclosure maybe used to determine whether the HTVS is hitting a bump or pothole,turning a corner, and/or accelerating. By accounting for dynamics of thetrailer and measuring angles and accelerations (e.g., in 3-dimensionalspace), embodiments of the present disclosure may provide formeasurement of: (i) acceleration, deceleration, and angle of inclinationof the trailer (e.g., by taking readings lengthwise), (ii) side-to-side(e.g., turning force) motion and banking of a roadway (e.g., by takingreadings widthwise), (iii) smoothness of the roadway, pot holes, and/orwheels riding on a shoulder (side) of the road (e.g., by taking readingsvertically). Utilizing such information, embodiments of the presentdisclosure may be used to brake wheels individually, for example, whilestill supplying power (e.g., by the power assist mode) to other wheels,thereby increasing trailer stability. In addition, and in someembodiments, by monitoring the acceleration, axle speed and incline ofthe roadway over time and by applying an incremental amount of torqueand measuring the response in real time, the controller mayback-calculate a mass of the trailer load. In some embodiments, a weightsensor may also be used, as described above. In either case, suchinformation may be used by the system for application of a proper amountof torque to assist in acceleration of the HTVS without over-pushing thepowered vehicle.

In some examples, the system may further be used to monitor one or morepneumatic brake lines, such that embodiments of the present disclosureprovide a ‘fail safe’ mode where the hybrid suspension system 100 willnot accelerate (e.g., operate in a power assist mode) while a driver(e.g. of the powered vehicle) is actuating a brake system. In variousembodiments, by monitoring feedback pressure of each wheel's brakelines, as well as their respective wheel speeds, the present system candetermine how each brake for a particular wheel is performing. Thus, invarious examples, embodiments of the present disclosure may provide forbraking and/or powering of different wheels independently from oneanother for increased trailer stability. In some cases, this may bereferred to as “torque vectoring”. By way of example, such torquevectoring embodiments may be particularly useful when there aredifferences in roadway surfaces upon which each of a plurality of wheelsof the HTVS is traveling (e.g., when roadway conditions areinconsistent, slippery, rough, etc.).

Embodiments disclosed herein may further be employed to recapture energyvia regenerative braking, as described above. In some examples, theapplication of the brakes, and/or various combinations of deceleration,axle speed, trailer weight and incline/decline readings may dictate, atleast in part, an ability and amount of regeneration possible by thehybrid suspension system 100. In various embodiments, regenerativebraking may persist until the energy storage system is fully charged,until a predetermined minimum level of stored energy has been achieved,or until the powered trailer axle has reached a minimum thresholdrotational speed. Additionally, for example in some extreme conditions,different amounts of braking may be applied to each wheel in order toreduce a potential of jack-knifing or other dangerous conditions duringoperation of the HTVS. As a whole, regenerative braking may be used tolighten a load on a mechanical braking system (e.g., on the poweredvehicle and/or on the trailer), thereby virtually eliminating a need fora loud compression release engine brake system (e.g., Jake brakesystem). In some cases, by applying both regenerative braking andfriction braking, the HTVS may be able to brake much faster and haveshorter stopping distances. In addition, and in various embodiments, thepresent system may be deployed with two pneumatic brake lines (e.g.,which may including existing brake lines), while an entirety of thecontrols (e.g., including sensor input processing, mode of operationcontrol, aspects of the various methods described above, and otherdecision-making controls) may reside entirely within the hybridsuspension system 100 itself (e.g., and in many respects, within thecontrol system 150).

Energy Capture and Management, Further Discussion

With respect to energy recapture, the above discussion is primarilydirected to charging the energy storage system (e.g., the battery array)by regenerative braking; however, other methods of energy recapture arepossible and within the scope of this disclosure. For example, in someembodiments, a hydraulic system (e.g., used to capture energy via airpressure or fluid pressure), flywheels, solar panels, or a combinationthereof may be used for energy recapture. Additionally, in some cases,the HVTS 160 may include shocks (e.g., as part of a suspension of thepowered vehicle and/or of the hybrid suspension system 100), which mayinclude regenerative shock absorbers, that may be used to captureelectrical energy via the motion and/or vibration of the shocks. In someembodiments, energy captured by one or more of the above methods may beused to charge the energy storage system.

Further, embodiments disclosed herein may use the recaptured energy notonly to apply the motive rotational force using the electricmotor-generator, but also to provide power that may be used for poweringa host of devices and/or systems, both on the trailer and on the poweredvehicle. For example, the recaptured energy may be used to power a liftgate, a refrigeration unit, a heating ventilation and air conditioning(HVAC) system, pumps, lighting, appliances, entertainment devices,communications systems, other 12V-powered devices, and/or to provide anauxiliary power unit (APU), among others. Regardless of where the poweris being provided, embodiments disclosed herein provide for energystorage and management to be on-trailer (e.g., via the battery array140, the master control unit 228, and the BMS 242).

When configured to provide an APU, the HVTS 160 may include an APUinterface to provide power from the energy storage system (e.g., thebattery array) to the powered vehicle to power one or more devicesand/or systems on the powered vehicle. In some embodiments, the APUinterface may include an SAE J2891 interface. In various examples, theAPU interface may physically couple to an electrical interface on thepowered vehicle so that power from the energy storage system may betransferred to the powered vehicle. In some embodiments, an inverter,such as the inverter described above, may be coupled between the energystorage system and the APU interface to supply AC power to the poweredvehicle. In some cases, a step-down DC-DC power supply may be coupledbetween the energy storage system and the APU interface to supply DCpower to the powered vehicle. In some embodiments, an electrical cablemay be used to transfer electrical power from the energy storage systemon the towed vehicle to the powered vehicle and for bi-directionallyconveying data between the powered vehicle and at least a batterymanagement system of the towed vehicle.

In at least some embodiments, a control interface is provided in thepowered towing vehicle. By way of example, the control interface may becoupled to the battery management system of the towed vehicle. Invarious embodiments, the control interface may provide anin-towing-vehicle (e.g., within a cab of the powered vehicle) display ofstate of charge for the energy storage system on the towed vehicle, aswitch or control of a switch to enable and disable supply of electricalpower to the powered towing vehicle, and/or mode control for selectivelycontrolling an operating mode of the battery management system. In someembodiments, and in at least one selectable mode of the batterymanagement system, energy recovered using the drive axle in aregenerative braking mode (or energy recovered using one of the othermethods described above) is used to bring the energy storage system to asubstantially full state of charge. Further, in some embodiments, and inat least another selectable mode of the battery management system, stateof charge of the energy storage system is managed to a dynamicallyvarying level based at least in part on uphill and downhill grades alonga current or predicted route of travel of the HVTS 160. In at least someembodiments, the control interface may be integrated with the HVACsystem on the powered towing vehicle, the HVAC system powered from theenergy storage system on the towed vehicle at least during some extendedperiods of time during which an engine of the towing vehicle is off(e.g., when the HVTS 160 is stopped at a rest area, weigh station,pick-up location, drop-off location, or other location).

Computer System for Implementing the Various Methods

Referring now to FIG. 7, an embodiment of a computer system 700 suitablefor implementing various aspects of the control system 150 and methods500, 550, is illustrated. It should be appreciated that any of a varietyof systems which are used for carrying out the methods described herein,as discussed above, may be implemented as the computer system 700 in amanner as follows.

In accordance with various embodiments of the present disclosure,computer system 700, such as a computer and/or a network server,includes a bus 702 or other communication mechanism for communicatinginformation, which interconnects subsystems and components, such as aprocessing component 704 (e.g., processor, micro-controller, digitalsignal processor (DSP), etc.), a system memory component 706 (e.g.,RAM), a static storage component 708 (e.g., ROM), a disk drive component710 (e.g., magnetic or optical), a network interface component 712(e.g., modem or Ethernet card), a display component 714 (e.g., CRT orLCD), an input component 718 (e.g., keyboard, keypad, or virtualkeyboard), a cursor control component 720 (e.g., mouse, pointer, ortrackball), a location determination component 722 (e.g., a GlobalPositioning System (GPS) device as illustrated, a cell towertriangulation device, and/or a variety of other location determinationdevices known in the art), and/or a camera component 723. In oneimplementation, the disk drive component 710 may comprise a databasehaving one or more disk drive components.

In accordance with embodiments of the present disclosure, the computersystem 700 performs specific operations by the processor 704 executingone or more sequences of instructions contained in the memory component706, such as described herein with respect to the control system 150 andmethods 500, 550. Such instructions may be read into the system memorycomponent 706 from another computer readable medium, such as the staticstorage component 708 or the disk drive component 710. In otherembodiments, hard-wired circuitry may be used in place of or incombination with software instructions to implement the presentdisclosure.

Logic may be encoded in a computer readable medium, which may refer toany medium that participates in providing instructions to the processor704 for execution. Such a medium may take many forms, including but notlimited to, non-volatile media, volatile media, and transmission media.In one embodiment, the computer readable medium is non-transitory. Invarious implementations, non-volatile media includes optical or magneticdisks, such as the disk drive component 710, volatile media includesdynamic memory, such as the system memory component 706, andtransmission media includes coaxial cables, copper wire, and fiberoptics, including wires that comprise the bus 702. In one example,transmission media may take the form of acoustic or light waves, such asthose generated during radio wave and infrared data communications.

Some common forms of computer readable media includes, for example,floppy disk, flexible disk, hard disk, magnetic tape, any other magneticmedium, CD-ROM, any other optical medium, punch cards, paper tape, anyother physical medium with patterns of holes, RAM, PROM, EPROM,FLASH-EPROM, any other memory chip or cartridge, carrier wave, or anyother medium from which a computer is adapted to read. In oneembodiment, the computer readable media is non-transitory.

In various embodiments of the present disclosure, execution ofinstruction sequences to practice the present disclosure may beperformed by the computer system 700. In various other embodiments ofthe present disclosure, a plurality of the computer systems 700 coupledby a communication link 724 to a network (e.g., such as a LAN, WLAN,PTSN, and/or various other wired or wireless networks, includingtelecommunications, mobile, and cellular phone networks) may performinstruction sequences to practice the present disclosure in coordinationwith one another.

The computer system 700 may transmit and receive messages, data,information and instructions, including one or more programs (i.e.,application code) through the communication link 724 and the networkinterface component 712. The network interface component 712 may includean antenna, either separate or integrated, to enable transmission andreception via the communication link 724. Received program code may beexecuted by processor 704 as received and/or stored in disk drivecomponent 710 or some other non-volatile storage component forexecution.

Where applicable, various embodiments provided by the present disclosuremay be implemented using hardware, software, or combinations of hardwareand software. Also, where applicable, the various hardware componentsand/or software components set forth herein may be combined intocomposite components comprising software, hardware, and/or both withoutdeparting from the scope of the present disclosure. Where applicable,the various hardware components and/or software components set forthherein may be separated into sub-components comprising software,hardware, or both without departing from the scope of the presentdisclosure. In addition, where applicable, it is contemplated thatsoftware components may be implemented as hardware components andvice-versa.

Software, in accordance with the present disclosure, such as programcode and/or data, may be stored on one or more computer readablemediums. It is also contemplated that software identified herein may beimplemented using one or more general purpose or specific purposecomputers and/or computer systems, networked and/or otherwise. Whereapplicable, the ordering of various steps described herein may bechanged, combined into composite steps, and/or separated into sub-stepsto provide features described herein.

What is claimed is:
 1. An apparatus comprising: a towed vehicle for usein combination with a towing vehicle, the towed vehicle having anelectrically powered drive axle configured to supply supplemental torqueto one or more wheels of the towed vehicle and to thereby supplement,while the towed vehicle travels over a roadway and in at least somemodes of operation, primary motive forces applied through a separatedrivetrain of the towing vehicle; an energy store on the towed vehicle,the energy store configured to supply the electrically powered driveaxle with electrical power and further configured to receive energyrecovered using the drive axle in a regenerative braking mode ofoperation; and an auxiliary power unit (APU) interface to supplyelectrical power from the energy store to the towing vehicle.
 2. Theapparatus of claim 1, further comprising: the towing vehicle; and aheating, ventilation or cooling system on the towing vehicle, theheating, ventilation or cooling system coupled to receive electricalpower from the energy store on the towed vehicle via the APU interface.3. The apparatus of claim 1, wherein the energy store on the towedvehicle includes a battery or battery array.
 4. The apparatus of claim3, further comprising: an inverter coupled between the battery orbattery array and the APU interface to supply AC power to the towingvehicle.
 5. The apparatus of claim 3, further comprising: a step-downDC-DC power supply coupled between the battery or battery array and theAPU interface to supply DC power to the towing vehicle.
 6. The apparatusof claim 3, further comprising: an electrical cable for transferringelectrical power from the energy store on the towed vehicle to towingvehicle and for bidirectionally conveying data between the towingvehicle and at least a battery management system of the towed vehicle.7. The apparatus of claim 6, further comprising: a control interface inthe towing vehicle, the control interface coupled to the batterymanagement system of the towed vehicle via the electrical cable, thecontrol interface providing one of more of: in-towing-vehicle display ofstate of charge for the energy store on the towed vehicle; a switch orcontrol of a switch to enable and disable supply of electrical power tothe towing vehicle; and mode control for selectively controlling anoperating mode of the battery management system, wherein in at least oneselectable mode, energy recovered using the drive axle in a regenerativebraking mode is used to bring the energy store to a substantially fullstate of charge, and wherein in at least another selectable mode, stateof charge is managed to a dynamically varying level based at least inpart on uphill and downhill grades along current or predicted route oftravel.
 8. The apparatus of claim 7, wherein the control interface isintegrated with a heating, ventilation or cooling system on the towingvehicle, the heating, ventilation or cooling system powered from theenergy store on the towed vehicle at least during some extended periodsof time during which an engine of the towing vehicle is off.
 9. A methodcomprising: supplying supplemental torque to one or more wheels of atowed vehicle using an electrically powered drive axle on the towedvehicle to supplement, while the towed vehicle travels over a roadwayand in at least some modes of operation, primary motive forces appliedthrough a separate drivetrain of a towing vehicle; supplying theelectrically powered drive axle with electrical power from an energystore on the towed vehicle, the energy store configured to receive andstore energy recovered using the drive axle in a regenerative brakingmode of operation; and supplying electrical power to the towing vehiclefrom the energy store on the towed vehicle by way of an auxiliary powerunit (APU) interface.
 10. The method of claim 9, further comprising:supplying electrical power from the energy store on the towed vehicle toa heating, ventilation or cooling system on the towing vehicle.
 11. Themethod of claim 10, wherein the energy store on the towed vehicleincludes a battery or battery array.
 12. The method of claim 11, furthercomprising: using an inverter coupled between the battery or batteryarray and the APU interface to supply AC power to the towing vehicle.13. The method of claim 11, further comprising: using a step-down DC-DCpower supply coupled between the battery or battery array and the APUinterface to supply DC power to the towing vehicle.
 14. The method ofclaim 11, further comprising: transferring electrical power from theenergy store on the towed vehicle to towing vehicle via an electricalcable; and bidirectionally conveying data between the towing vehicle andat least a battery management system of the towed vehicle via theelectrical cable.
 15. The method of claim 14, further comprising:providing a control interface in the towing vehicle, the controlinterface coupled to the battery management system of the towed vehiclevia the electrical cable, the control interface including one of moreof: in-towing-vehicle display of state of charge for the energy store onthe towed vehicle; a switch or control of a switch to enable and disablesupply of electrical power to the towing vehicle; and mode control forselectively controlling an operating mode of the battery managementsystem, wherein in at least one selectable mode, energy recovered usingthe drive axle in a regenerative braking mode is used to bring theenergy store to a substantially full state of charge, and wherein in atleast another selectable mode, state of charge is managed to adynamically varying level based at least in part on uphill and downhillgrades along current or predicted route of travel.
 16. The method ofclaim 15, wherein the control interface is integrated with the heating,ventilation or cooling system on the towing vehicle, the heating,ventilation or cooling system powered from the energy store on the towedvehicle at least during some extended periods of time during which anengine of the towing-vehicle is off.
 17. The method of claim 9, furthercomprising: selectively controlling an operating mode of a batterymanagement system, wherein in at least one selectable mode, energyrecovered using the drive axle in a regenerative braking mode is used tobring the energy store to a substantially full state of charge, andwherein in at least another selectable mode, state of charge is managedto a dynamically varying level based at least in part on uphill anddownhill grades along current or predicted route of travel.
 18. Themethod of claim 17, wherein the selective control is provided from acontrol interface of a heating, ventilation or cooling system on thetowing vehicle.